1. Field of the Invention
The invention relates to the improvement provided to the rollers which are coated with elastic material, found in the drafting and guiding zone, and used in yarn production techniques, by apron cladding having shift structure and pre-tensioning mechanism.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Nowadays, in almost all of the yarn production techniques, rollers coated with elastic material are used either for drafting purposes or with the purpose of guiding the yarn to the next stage. The yarn, according to the place it is used either in fibre form or in its final form, contacts these rollers with a certain tension and it is exposed to drafting or guiding process via these rollers.
Material hardness of the rollers coated with elastic material is directly related with the quality of the yarn produced and its function, and the elastic material hardness of the top rollers at the drafting zone is especially important for the quality of the yarn.
It is a known situation that the contact of the fibre or the yarn with the roller coated with elastic material has an abrasive effect. As the application point allows, the machine producers move the fibre or the yarn on the rollers on which they are guided or drafted in order to delay the abrasion of the elastic material and extend its operation period.
Compact ring yarn spinning technique is an important example in which the abrasion in the rollers coated with elastic material is intensive. In the compact spinning technology, yarns are positioned closer to each other by using a compacting zone just after the main drafting zone, and thus the spinning triangle is almost removed. In this way, the improvement of the properties of the yarn, for example increasing its strength, and reducing its hairiness is aimed.
One of the compact ring yarn production techniques is the mechanical compactor mechanism. In FIGS. 1 and 2, the views of the prior mechanical compactor mechanism is given and the operating principle of this mechanism will be explained below by making references to the reference numbers found in the figures. In FIG. 1, the side schematic view of the mechanical compactor mechanism used in the prior art for producing compact yarn is given. In FIG. 2, the detail view showing the positions of the mechanical compactor and the rollers relative to each other is given. As it is seen in the figures, a Delivery drafting roller (1) initiated by the gearbox, supports the Top roller (9) and the Front roller (10) belonging to the compaction zone. The contact point of the compaction zone is between the points A and B shown in FIG. 2. The mechanical compactor (12), which is a precision instrument, presses on the Delivery drafting roller (1) without any gaps. The mechanical compactor (12) forms a completely closed compaction room together with the Delivery drafting roller (1), and the Delivery drafting roller (1) surface moves together with the fibres synchronously in order to guide these fibres to the compactor (12) precisely. As it is seen in the detail view of the A-B compaction part, a compaction channel (12.1) is found at the inner part of the mechanical compactor (12), which has a funnel shaped structure narrowing downwardly. The fibres entering through the Delivery drafting roller (1) and the Top roller (9) are compacted while they go downwards through the compaction channel (12.1) which is found at the inner part of the mechanical compactor (12). When the compacted fibres go out of the channel (12.1), they are exposed to winding operation by passing through the Front roller (10) and the Delivery drafting roller (1) and they become high durability yarn.
As it is seen in FIG. 1, mechanical compact yarn production mechanism according to the prior art comprises a Delivery drafting roller (1), which is made of metal based material and which makes rotational motion by being initiated by the gearbox and a Middle drafting roller (2), a roving guide (11) which operates as a guide for providing entrance of large numbers of fibre into the mechanism, a bottom apron (8) which is placed over a Middle drafting roller (2) and the Bottom apron guide bar (6), and a Top apron (7) which is placed over the Top apron roller (5) and the Apron cradle (4). Fibres entering from the roving guide (11) are compacted by passing through the top and the bottom apron (7,8). Fibres passing through the top and the bottom apron (7,8) reach between the Delivery drafting roller (1) and the Top roller (9). Via a pressure arm (3) of the mechanism, the Top roller (9) made of rubber material is pressed onto the Delivery drafting roller (1) with a certain force. The drafted and expanded fibres which passed through the Delivery drafting roller (1) and the Top roller (9) are guided to the mechanical compactor (12). Since the fibres pass through almost at the same place, abrasions occur at the rubber Top roller (9) surface and these deformations increase when the operation hours extend. Due to the deformations on the rubber surface, problems occur such as frequent grinding or renewal labour for the Top roller (9), loss of production, and quality differences between spindles. Yarn end brakes per average of 1000 spindles increase with the deformations at the surface, and problems occur due to the abundance of quality error cleaning in winding, which is the next operation, and therefore the expenses of maintenance increase. Moreover, in the prior mechanism, the fibres (20) which cannot enter the compactor (12) during spinning (FIG. 6A) generate fluffs, and these fluffs causes environment and machine pollution and/or it is added to the yarn structure at the spinning zone in an uncontrolled way. This situation makes negative impact on the yarn quality and operation conditions. Since the position of the clearer roller (18) shown in FIG. 6A is distant from the fibres (20) that can not enter the compactor, it is not effective in accumulating fibres on itself.
About the mechanical compact yarn production mechanism, the application with publication number WO 2006005207 is found as the closest document to the mechanism, which is the subject of the invention. However, when this patent document is examined, it can be seen that adequate solution suggestions are not provided in this document for eliminating the above said drawbacks and problems.
As a result, the inadequacy of the prior solutions have necessitated an improvement on the related field, which reduces the abrasion tendency at the rollers coated with elastic material for drafting and guiding purposes in the yarn production techniques, eliminates the said drawbacks and disadvantages in the mechanical ring compact spinning which is especially the basis of operation, improves the yarn parameters, and provides more efficient operation conditions.
3. Disadvantages of the Prior Art:
In the known status of the art, the abrasive impact on the elastic material and the coated surface as a result of the contact between the rollers coated with elastic material and the fibre or the yarn is inevitable after a certain period. Guiding of the fibre or the yarn to the rollers coated with elastic material by continuous moving, use of elastic material developed with different formulas, and choosing the roller dimensions in the smallest diameters and widths that can be used according to the application point are the applications for delaying this abrasion impact.
Despite all these measures, in the spinning techniques in which the fibre or the yarn is guided to the roller coated with elastic material without moving to the left or to the right or with a very little moving distance;
1. Maintenance labours due to abrasion in very short periods
2. Quality problems due to rapid abrasion
3. Great quality deviations between production units, and
4. Negative operating conditions due to abrasion originating impacts such as breaks, laps etc. are observed.
Since the fibres pass through almost at the same place also in the prior mechanical compact ring spinning system, they rapidly cause abrasion at the place that they pass through on the Top roller (9). As a result of this, deformations occur in the yarn quality parameters and operating conditions. In order to prevent such an undesired condition, the Top roller (9) has to be grinded and renewed in very short periods. After each grinding, diameter of the Top roller (9) decreases and due to the decreased rubber amount, the hardness impact of the Top roller (9) increases. This situation ruins the fibre expanding property between the Top roller (9) and Delivery drafting roller (1).
Ineffective Removal of the Fluffs Occurring at the Compactor Zone:
In FIG. 6a, fibres (20) that cannot go through the compactor (12) during the spinning operation in the present system are shown. Perspective view given in FIG. 6b shows the distance of the clearer roller (18) to the fibres (20) coming out in between the top roller (9) and compactor (12) in the prior art. This distance is not sufficient for clearer roller (18) to collect the fibres (20) that cannot go through the compactor on itself.
The fibres (20) that can not enter the compactors generate fluffs, and these fluffs causes environment and machine pollution and/or it is added to the yarn structure at the spinning zone in an uncontrolled manner. This situation makes negative impact on the yarn quality and operation conditions.